Open Access
Changes in long-term light properties of a mixed conifer–broadleaf forest in Southwestern Europe
(MDPI, 2021) Ruiz de la Cuesta Vela, Ignacio; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Peralta de Andrés, Francisco Javier; Rodríguez Pérez, Javier; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Natural and anthropogenic factors affect forest structure worldwide, primarily affecting forest canopy and its light properties. However, not only stand-replacing events modify canopy structure, but disturbances of lower intensity can also have important ecological implications. To study such effects, we analyzed long-term changes in light properties of a conifer–broadleaf mixed forest in the Southwestern Pyrenees, placed in the fringe between the Mediterranean and Eurosi- berian biogeographical regions. At this site, a thinning trial with different intensities (0%, 20%, and 30–40% basal area removed) took place in 1999 and 2009, windstorms affected some plots in 2009 and droughts were recurrent during the sampling period (2003, 2005, 2011). We monitored light properties during 14 years (2005–2019) with hemispherical photographs. We applied partial autocorrelation functions to determine if changes between years could be attributed to internal canopy changes or to external disturbances. In addition, we mapped the broadleaf canopy in 2003, 2008, and 2016 to calculate broadleaf canopy cover and richness at the sampling points with different buffer areas of in- creasing surface. We applied generalized linear mixed models to evaluate the effects of light variables on canopy richness and cover. We found that light variables had the most important changes during the period 2008 to 2010, reacting to the changes caused that year by the combined effects of wind and forest management. In addition, we found that an area of 4.0 m radius around the sampling points was the best to explain the relationship between light properties and species richness, whereas a radius of 1.0 m was enough to estimate the relationship between light and canopy cover. In addition, light-related variables such as diffuse light and leaf area index were related to species richness, whereas structural variables such as canopy openness were related to canopy cover. In summary, our study demonstrates that non stand-replacing disturbances such as windstorms, thinning, or droughts can have an important role in modifying structural and light-related canopy properties, which in turn may inﬂuence natural processes of stand development and ecological succession.
Open Access
Increased complementarity in water-limited environments in Scots pine and European beech mixtures under climate change
(Wiley, 2017) González de Andrés, Ester; Seely, Brad; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Lo, Yueh-Hsin; Castillo Martínez, Federico; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Management of mixedwoods is advocated as an effective adaptation strategy to increase ecosystem resiliency in the context of climate change. While mixedwoods have been shown to have greater resource use efficiency relative to pure stands, considerable uncertainty remains with respect to the underlying ecological processes. We explored species interactions in Scots pine / European beech mixedwoods with the process-based model FORECAST Climate. The model was calibrated for two contrasting forests in the southwestern Pyrenees (northern Spain): a wet Mediterranean site at 625 m.a.s.l. and a subalpine site at 1335 m.a.s.l. Predicted mixedwood yield was higher than that for beech stands but lower than pine stands. When simulating climate change, mixedwood yield was reduced at the Mediterranean site (-33%) but increased at the subalpine site (+11%). Interaction effects were enhanced as stands developed. Complementarity dominated the Mediterranean stand but neutral or net competition dominated the subalpine stand, which had higher stand density and water availability. Reduced water demand and consumption, increased canopy interception, and improved water-use efficiency in mixtures compared to beech stands suggest a release of beech intra-specific competition. Beech also facilitated pine growth through better litter quality, non-symbiotic nitrogen fixation and above- and belowground stratification, leading to higher foliar nitrogen content and deeper canopies in pines. In conclusion, mixtures may improve water availability and use efficiency for beech and light interception for pine, the main limiting factors for each species, respectively. Encouraging pine-beech mixtures could be an effective adaptation to climate change in drought-prone sites in the Mediterranean region.
Open Access
Incendios forestales: reseña
(Asociación Española de Ecología Terrestre, 2012) Blanco Vaca, Juan Antonio; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
El libro describe de una forma amena el estado actual del conocimiento científico sobre los incendios forestales. Este libro no muestra los incendios como el desastre natural que aparece reflejado continuamente en los medios de comunicación, ni tampoco como una mera perturbación del ecosistema, el modo tradicionalmente descrito por los ecólogos. Por el contrario, el autor presenta los incendios forestales como parte integrante de los ecosistemas, como un factor que ha afectado a la evolución de las comunidades vegetales y que las mantiene en un estado determinado.
Open Access
A global synthesis on the effects of forest thinning on hydrological processes: implications for forest management
(Elsevier, 2022) Campo, Antonio D. del; Otsuki, Kyoichi; Serengil, Yusuf; Blanco Vaca, Juan Antonio; Yousefpour, Rasoul; Wei, Xiaohua; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias
Forest thinning can significantly affect hydrological processes. However, these effects largely vary with forest types, climate, thinning intensity, and hydrological variables of interest. Understanding these effects and their variations can significantly support thinning treatments’ design and selection to ensure desired hydrological benefits. In this global-level review paper, we report the first comprehensive meta-analysis on the effects of thinning on major hydrological processes with an emphasis on rainfall partitioning, soil moisture and evapotranspiration processes. The synthesized and reviewed studies encompass different biophysical conditions (climate and forest ecosystems), silvicultural systems, and time scales (from weeks to decades) across continents. The results showed a significant increase in net precipitation, soil moisture and tree-level water use after thinning (the effect sizes are 1.19, 1.14 and 1.56 relative to the value of the control, respectively), while decreases in stemflow and transpiration (the effect sizes of 0.42 and 0.6 relative to the value of the control, respectively). Thinning intensity of about 50% of the stand density is determined as the threshold at or over which hydrological processes are significantly affected. The duration of thinning effect can be set between 2.6 and 4.3 (throughfall) and 3.1–8.6 years (soil moisture and transpiration), asking for repeated thinning in order to effectively sustain these effects. These global averages can serve as benchmarks for assessment and comparisons, but the effects of thinning depend on local biophysical conditions and thinning treatments. The literature review on the rest of the studied hydrological variables suggests that thinning generally enhance runoff to increase water yield and groundwater recharge. Thinning can also have a positive or limited role in water use efficiency (WUE), but it mitigates the effects of drought through increasing WUE. Moderate adverse effects on water quality can be prevented by adequate forest managements to prevent soil degradation. Nevertheless, more researches at relatively less studied regions are needed to support a more robust analysis of these reviewed hydrological variables. The management implications of the synthesized and reviewed results are suggested and discussed within the context of climate change.
Open Access
8ª Edición de la Escuela de verano de Ecología de Navarra: ecólogas/os por un día
(Asociación Española de Ecología Terrestre, AEET, 2022) Imbert Rodríguez, Bosco; Blanco Vaca, Juan Antonio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Durante los pasados 23 y 24 de junio tuvo lugar la 8ª edición de la Escuela de Verano de Ecología de Navarra de la Universidad Pública de Navarra (UPNA) con el título ‘Ecólogas/os por un día’. En la jornada se impartieron cuatro ponencias por parte de los miembros del grupo de investigación de Ecología y Medio Ambiente de la Universidad Pública de Navarra, pero la mayor parte del tiempo se dedicó al trabajo de campo en el parque. En dicho trabajo de campo los asistentes pudieron trabajar tres temas diferentes: el estudio de las comunidades vegetales en pastos, el estudio de la estructura de una comunidad arbórea y la observación y estimación de censos de aves. Los trabajos incluyeron la demostración y familiarización de los estudiantes con las distintas técnicas y aparatos para medir variables ambientales como luz ambiental, temperatura del suelo, humedad del suelo, diámetro y altura de árboles, así como las técnicas para realizar inventarios florísticos o de fauna.
Open Access
Sustainable management of metasequoia glyptostroboides plantation forests in Shanghai
(MDPI, 2018) Zheng, Ji; Blanco Vaca, Juan Antonio; Wei, Xiaohua; Liu, Chunjiang; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Urban forestry is increasingly used as a tool for climate change mitigation and for providing environmental services to inhabitants of urban areas. However, tree species used in urban forestry are usually different from the ones used in commercial forestry. As a consequence, available data on growth and yield under alternative management scenarios are usually scarce. As forest models can be used to explore potential forest futures, they are of special interest as decision-support tools in urban forestry. In this research, we used the FORECAST ecosystem-level forest model to deﬁne the management prescriptions for Metasequoia glyptostroboides plantations in Shanghai that reach the highest net primary productivity (NPP). In a ﬁrst step, a battery of different stand densities (from 500 to 4000 stems ha−1) was used to identify those with the highest NPP at stand level. Then, different thinning regimes (with intensities ranging from 15% to 40% of trees removed and applied at stand age 5 to 20 years) were simulated on those initial densities with the highest NPP (3000 and 4000 stems ha−1). Planting 4000 stems ha−1 and not applying thinning achieved the highest annual NPP (14.39 ± 3.92 Mg ha−1 year−1) during the ﬁrst rotation, but it was not signiﬁcantly different from the NPP achieved with the same initial density but thinning 40% of trees at year 10. NPP was estimated to decrease with consecutive rotations, and for the second rotation thinning was needed to signiﬁcantly increase NPP (10.11 ± 2.59 Mg ha−1 year−1 with 4000 stems ha−1 and 25% thinning at year 10) above non-thinning management. For the third rotation, the highest NPP was reached with initial density 3000 stems ha−1 and 25% thinning at year 10. Nitrogen ﬂows were also estimated to decrease with consecutive rotations. These results indicate the potential of managing M. glyptostroboides urban plantations to reach their maximum productivity potential, but also that additional actions would be needed to ensure adequate nutrient levels over consecutive rotations. For a species such as M. glyptostroboides, which was discovered for science less than 70 years ago and for which no plantations over 50 years exist, the ecosystem-level FORECAST model has been shown as a suitable tool to support management decision when growth and yield data are not available.
Open Access
Calculadora de sostenibilidad FIRST-Heat Navarra: generando energía sostenible al reducir el riesgo de incendios forestales en comunidades rurales
(Sociedad Española de Ciencias Forestales, 2020) Candel Pérez, David; Blanco Vaca, Juan Antonio; Lo, Yueh-Hsin; Montero, Eduardo; Barrena Figueroa, Ramo; Castillo Martínez, Federico; Ciencias; Zientziak; Gestión de Empresas; Enpresen Kudeaketa
El cambio climático, la expansión urbanística o el aumento del uso recreativo en zonas forestales están aumentando la probabilidad de ocurrencia de incendios forestales. Las comunidades rurales pueden afrontar la oportunidad de combinar actividades silvícolas para reducir el riesgo de incendios con el desarrollo energético basado en el aprovechamiento de la biomasa forestal generada. Para demostrar la viabilidad de este tipo de gestión, se ha creado una herramienta informática demostrativa de apoyo a la toma de decisiones. Mediante la modificación y calibración del modelo ecológico FORECAST, se simularon las condiciones de diferentes localidades y especies forestales de Navarra. Sobre dichas simulaciones, se ha desarrollado la interfaz de usuario de esta calculadora (Fire Interface Rural Screening Tool for Heating: FIRST-Heat Navarra), que pretende estimar la sostenibilidad ecológica y socio-económica del uso de la biomasa forestal a nivel local. Esta herramienta se muestra capaz de simular los efectos del cambio en las condiciones de crecimiento del bosque mediante un modelo ecológico dinámico. También presenta la capacidad de integrar, resumir y comunicar de forma efectiva el último conocimiento científico sobre ecología forestal, y el conocimiento técnico, económico y social sobre la tecnología de calefacción de distrito a partir de biomasa.
Embargo
Editorial: Ecological models for tomorrow's solutions
(Elsevier, 2025-07-01) Arhonditsis, George; Blanco Vaca, Juan Antonio; Wang, Hsiao-Hsuan; Neuman, Alexey; Arnillas, Carlos A.; Fath, Brian D.; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
A robust environmental policy analysis typically relies upon the following pillars: (i) defensible identification of the critical drivers of degradation, (ii) elucidation of the sources of controversy, and (iii) development of necessary tools to anticipate the unexpected. While management problems are rarely (if ever) solved completely and certain facets of environmental/ecological systems evolve over time (Davies et al., 2024), the core issues remain the same. It is thus critical to establish knowledge frameworks that ensure both continuity in the decision-making process but also iterative adjustments to accommodate the ubiquitous uncertainty surrounding the study of open ecosystems.
Open Access
Modelos ecológicos: descripción, explicación y predición
(Asociación Española de Ecología Terrestre, 2013) Blanco Vaca, Juan Antonio; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Los ecosistemas son, por definición, complejos sistemas en los que factores biológicos, climáticos y geológicos se combinan con factores sociales, políticos y económicos para producir una serie de procesos ambientales que determinan la evolución de cada uno de estos ecosistemas en el tiempo. Esto hace que el estudio y la gestión de cualquier ecosistema sea un asunto siempre complejo. Por ello, cualquier herramienta que permita simplificar el estudio de estos factores y predecir los efectos de alterar alguno de ellos es de gran ayuda tanto en la investigación como en la gestión de los ecosistemas (Blanco 2013). La aplicación de la ciencia de la ecología a la investigación y gestión de los ecosistemas requiere del abordaje de tres componentes complementarios: conocer, entender y predecir. “Conocer” es análogo a una descripción de un fotograma. “Entender” es análogo a examinar los componentes de cada fotograma y cómo encajan unos con otros. “Predecir” es hacer una película reuniendo los fotogramas que proporcionan fotos estáticas del sistema en diferentes momentos. Cada una de estas partes es necesaria para la resolución de problemas complejos, y ninguna es suficiente de forma aislada. Solamente cuando se combinan las tres partes se pueden alcanzar los objetivos y proporcionar una base adecuada para guiar la compleja relación entre la humanidad y los recursos naturales. La comunicación es considerada una cuarta parte de la ciencia, ya que la ciencia que no se comunica no contribuye al avance de la humanidad en la búsqueda de una forma de vida más sostenible con nuestro ambiente. La comunicación es requerida en los tres componentes de la ciencia, y este monográfico de Ecosistemas es parte de ese esfuerzo por parte de los científicos para comunicar sus hallazgos.
Open Access
Sensitivity of long-term productivity estimations in mixed forests to uncertain parameters related to fine roots.
(Elsevier, 2024) Yeste Yeste, Antonio; Seely, Brad; Imbert Rodríguez, Bosco; Blanco Vaca, Juan Antonio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Forest growth models are increasingly being used in forestry and ecology research as predictive tools to help developing practical guidelines and to improve understanding of the drivers of forest ecosystem functioning. Models are usually calibrated using parameters directly obtained or estimated from empirical field observation, and hence are subject to uncertainty. Thus, output accuracy depends on input parameters precision and on how influential is each parameter on model behaviour. Hence, it is important to analyse parameter-related uncertainty and its effects on model outputs. This can be done by performing sensitivity analyses, which allow to explore the influence of one or several calibration parameters on model outputs. As studies on tree root parameters are particularly scarce, the aim of the present work was to evaluate the influence of parameters related to fine roots on estimations of long-term forest growth patterns in pure and mixed forests, using FORECAST (a hybrid forest growth model) as a virtual lab. The fine root parameters assessed were biomass, turnover rate, and nitrogen content. The analysis was performed by simulating monospecific stands of two contrasting species (Pinus sylvestris L. and Fagus sylvatica L.), and mixed stands formed by both species. In all cases, FORECAST showed good capability to contain uncertainty propagation during the first and middle stages of stand development (<40 years). After that moment, model output uncertainty steadily increased, but it reached different maximum uncertainty levels depending on stand type. Simulations of the less nutrient demanding P. sylvestris manifested very little sensitivity when growing in monospecific stands. However, F. sylvatica monospecific stands showed intermediate sensitivity, but significant species interactions occurred in mixed stands that determined the biggest impact detected of uncertainty related to fine root parameters over model outputs. All things considered, FORECAST displayed an interesting capability to capture some of the interspecific interactions that are key in mixed forests functioning. Our results suggest an acceptable model performance under uncertain parameterization but also caution against expecting accurate quantitative estimations of forest growth, especially when considering long-term scenarios in complex mixed stands.